Troublesome black plastic could be recycled to create renewable energy

Black plastic could finally be recycled as a way to create new materials useful in the generation of renewable energy.

As efforts to recycle more of our household waste increase, black plastic remains a major problem as many automated recycling machines are unable to identify it on a conveyor belt. However, researchers at Swansea University have found a way to take this troublesome material and give it new life after it’s thrown away.

In a paper published to the Journal of Carbon Research, the researchers described a method that allows them to create new materials, such as wires, from discarded black plastic. These wires could be used for conducting electricity and, in particular, cabling for renewable energy projects.

Plastics are made from carbon, hydrogen and oxygen, with the amounts and arrangements of these elements often varying in complexity. As plastics are very pure and highly refined chemicals, they can be broken down into these elements and then bonded in different arrangements to make high-value materials such as carbon nanotubes.

“The structure of a carbon nanotube looks a piece of chicken wire wrapped into a cylinder, and when carbon is arranged like this it can conduct both heat and electricity,” said Dr Alvin Orbaek White. “These two different forms of energy are each very important to control and use in the right quantities, depending on your needs.”

He added that it could be used within conductive films for touchscreen displays, flexible electronics fabrics that create energy, and antennas for 5G networks.

Solving a significant issue

As part of the study, the researchers tested a range of different plastics – but particularly black plastics – used in a variety of ready meals and supermarket packaging that often can’t be recycled. They removed the carbon and then constructed nanotube molecules from the bottom up using the carbon atoms, and used the nanotubes to transmit electricity to a light bulb in a small demonstrator model.

They now plan to make high-purity carbon electrical cables using plastic waste and improve the nanotube material’s performance to make them ready for large-scale deployment in the next three years.

“The research is significant as carbon nanotubes can be used to solve the problem of electricity cables overheating and failing, which is responsible for about 8pc of electricity … lost in transmission and distribution globally,” Orbaek White said.

“This may not seem like much but it is low because electricity cables are short, which means that power stations have to be close to the location where electricity is used, otherwise the energy is lost in transmission.”